package model;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: xwl
 * Date: 2023-08-30
 * Time: 19:24
 */
public class BlogDao {
    // 把一个 Blog 对象插入到数据库中
    public void insert(Blog blog) {
        Connection connection = null;
        PreparedStatement statement = null;
        try {
            // 1.建立连接
            connection = DBUtil.getConnection();
            // 2.构造 sql
            String sql = "insert into blog values(null, ?, ?, ?, ?)";
            statement = connection.prepareStatement(sql);
            statement.setString(1, blog.getTitle());
            statement.setString(2, blog.getContent());
            statement.setInt(3, blog.getUserId());
            statement.setString(4, blog.getPostTime());
            // 3.执行 SQL
            //   用于执行数据库增删改查的 SQL 语句, 执行完后, 就会返回一个整数

            statement.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            // 把资源的关闭放到 finally 中是更好的选择, 以防前面的代码异常, 资源没能正常关闭
            DBUtil.close(connection, statement, null);
        }
    }

    // 查询 blog 表中所有的博客数据
    public List<Blog> selectAll() {
        List<Blog> blogs = new ArrayList<>();
        Connection connection = null;
        PreparedStatement statement = null;
        ResultSet resultSet = null;
        try {
            connection = DBUtil.getConnection();
            String sql = "select * from blog order by postTime desc";
            statement = connection.prepareStatement(sql);
            resultSet = statement.executeQuery();

            while (resultSet.next()) {
                Blog blog = new Blog();
                blog.setUserId(resultSet.getInt("userId"));
                blog.setBlogId(resultSet.getInt("blogId"));
                blog.setTitle(resultSet.getString("title"));
                String content = resultSet.getString("content");
                // 由于 摘要 没有单独字段, 可以在此处对 markdown 中的特殊字符进行替换(暂时只替换 #)
                content = content.replace('#', '\0');
                if (content.length() > 100) {
                    content = content.substring(0, 100) + "...";
                }

                blog.setContent(content);
                blog.setPostTime(resultSet.getTimestamp("postTime"));
                blogs.add(blog);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(connection, statement, resultSet);
        }
        return blogs;
    }

    // 指定一个 博客id 来查询对应的博客
    public Blog selectOne(int blogId) {
        Connection connection = null;
        PreparedStatement statement = null;
        ResultSet resultSet = null;
        try {
            connection = DBUtil.getConnection();
            String sql = "select * from blog where blogId = ?";
            statement = connection.prepareStatement(sql);
            statement.setInt(1, blogId );
            resultSet = statement.executeQuery();

            if (resultSet.next()) {
                Blog blog = new Blog();
                blog.setUserId(resultSet.getInt("userId"));
                blog.setBlogId(resultSet.getInt("blogId"));
                blog.setTitle(resultSet.getString("title"));
                blog.setContent(resultSet.getString("content"));
                blog.setPostTime(resultSet.getTimestamp("postTime"));
                return blog;
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(connection, statement, resultSet);
        }
        return null;
    }

    // 指定 博客id 来删除
    public void delete(int blogId) {
        Connection connection = null;
        PreparedStatement statement = null;
        try {
            connection = DBUtil.getConnection();
            String sql = "delete from blog where blogId = ?";
            statement = connection.prepareStatement(sql);
            statement.setInt(1, blogId);
            statement.executeUpdate();

        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(connection, statement, null);
        }
    }

}
